Here comes the modular mobile revolution

Modular gadgets are flexible, powerful, upgradeable and eco-friendly. What's not to love?

Because it's Google's, Project Ara is the best-known modular gadget project. But there are others. And all of them are really cool.

PhonebloksPhonebloks is a modular smartphone project that began a few years ago when a designer named Dave Hakkens experienced a broken smartphone camera. He was concerned about the waste involved in replacing the whole phone for a new one just because one component needed to be changed.

Phonebloks is not a product, but an initiative to encourage the entire consumer electronics industry to embrace modular smartphone development. In fact, the community that Phonebloks cultivated was central to the creation and evolution of Project Ara.

PuzzlePhone The Puzzlephone, from a company called Circular Devices, is a modular smartphone concept similar to Project Ara but simpler. Instead of having many different modules, the Puzzlephone can handle just two.

The base is mainly a screen which is designed to last 10 years. Another module is for the battery, and yet another is for the processing and electronics. The idea is that if your battery wears out, you can swap out the battery without wasting the rest. If you want to upgrade for performance, you can do that without throwing away the battery and screen.

The company says it will ship its first Puzzlephone by the end of the year. The initial offering will run Android, but Circular Devices says it may choose alternative operating systems like Windows Phone, Firefox OS or Sailfish OS. A single phone might even have OS modules. By swapping out the Android module and replacing it with a Windows module, you could hot-swap operating systems.

Nexpaq modular smartphone caseModularity for smartphones is nice, but it's requiring a wholesale architectural change to all aspects of smartphones. A lighter approach is to add modular features to a case, which attaches to an existing smartphone.

The Nexpaq has Apple iPhone 6 and Samsung Galaxy S5 and S6 versions and comes with six module slots.

The company has already developed 12 modules, including a breathalyzer, speaker, flash drive, USB module, extra battery and laser pointer.

MODR modular caseAnother modular case product is the MODR (currently being crowdfunded and available for pre-order on Indegogo), which takes an interesting approach: The base unit is a Qi-compatible wireless charger. On top of that module, there are slots for users to hot-swap in small new components.

The MODR offers a lens mount for using several lenses, a USB hub, an LED flashlight and an NFC module. It also has a battery pack and pico projection modules.